Distillation and coking of carbonaceous materials



1,640,502 A 3 L. HONIGMANN ET DISTILLATION AND COKING OF CAHBONACEOUS MATERIALS Filed Jan. 7, 1927 WWWLW Patented Aug. 3 0,: 1927.

UNITED STATES,

PATENT OFFICE.

MUNICH,

GERMANY. A

ms'rinna'rron Ann coxnie or cannonnonous MATERIALS.

Application filed January 7, 1927, Serial No In many furnaces and similar devices for v the drying and the distilling of fine granu-, lar material, this materialis spread outin a thin layer on a surface and exposed to the action of heat, the surface bearing the layer of material being usually passed through aheating or re-action chamber if the drying process is to be carried out in a continuous manner. Although it is also known that in the case of certain kinds of material to be dried, the spreading out in a thin and uniform layer is advantageous, in that the heating action andalso thewithdrawal of the vapours and gases are facilitated, vit has hitherto been held that the diminution in the thicknesss of the layer should not be carried beyond a certain limit, as otherwise the operation ceased-t0 be eco nomical owing to. the smallness of the quantity of material treated per unit of time. By a very .thin layer in this connection would be understood'a layer having a thickness' of a'few centimetres. The-factory treatment of material to be dried was regarded as impossible in layers of less than 1.5 cm.

Exhaustive experiments carried out by the inventors have yielded the surprising result that it is possible to work advantageously withlayers, the thickness of which is'of an order of magnitude altogether differentfrom what has hitherto been regarded as possible. Experiments, particularly with furnaces with'a revolving annular horizontal hearth, hereinafter referred to-as revolving ring plate furnaces, wherein upon the revolving hearth quite uniform layers of such thin layers consists in the direct are spread of a thickness amounting to not more than a few millimetres, have given altogether astonishing results, in that the output attained with the furnace has amounted to twentytimes, andmore than twenty times,'the output reached with layers of a thickness of a few centimetres In the case of fine granular material, the of such thin layers presents no.

spreading difilculty at all. The essential advantage almost instantaneous action of the heat. The layer can in this manner be successfully passed through a'comparatively small furnace chamber at a-high speed, t us effecting a complete heat treatment of the material. Thus for example wet peat having a water content' of from 50 to 55 percent, in a single 159,700, and in Germany November 26, 1925.

revolution of a small experimental" furnace,

was not only thoroughly dried, but also coked and freed from oil. The entire drying and distillation process was completely finished in a single revolution of the furnace, which only occupied 28 seconds andcomprised'a path of about; metres in length.

Accordingly. a process according to the: invention for the" drying or coking of fine granular material by heat treatment in a thin layer is characterized by the fact thatthe material is s readv out 1nto layers the" thickness of which amounts to fractions of a centimetre. Inapreferre d constructionalform of the employed in continuous operation in connection with very high speed revolving plate furnaces] The resultis to increase the output ofieach unit of heating surface per unit of time to a multiple of what it would be under ordinary circumstances. From this there follows the further advantage of being able to employ .verysmall and high speedrotating furnaces, revolving ring plate furnaces for example, whereby for'the same output there weighed quantitiesof fine'granular lignitein layers of different thicknesses, in such a way that the material completely covered the heating surface in an exactly" uniform layer. Each'layer of material was left on the heating surface until completely dried and then removed. The duration of each drying operationwas accurately determined. First of all a'weighed quantity was spread out in a layer 15 millimetres in thickness corresponding to the smallest thickness 0 ,layer hitherto regarded as practicable. After the complete drying ofthis quantity, three times the same quantity by weight of moist coal was divided, firstly into 15 parts, secondly in to 7.5 parts, and finally into 5 parts. Thereupom'of the quantity divided into 15 :parts, the 15 parts were taken in successionfone at a time and spread on the plate,

to p

new I process, layers of such. thickness are substances.

giving on each occasions layer millimetre in thickness, and each of these 15 layers same water content-when spread out in a,

layer only 1 millimetre thick, 14.13 times as long as when spread out in a layer 2 millimetres thick, and 8.55 times as long as when spread out in a layer 3 millimetres thick.

Hence for a layer l'millimetre thick the output was 15.02, 2 millimetres thick the output was 14.13, 3 millimetres thick the output was 8.55 times as great as in the case of a layer 15 millimetres thick.

The present process is however of particular value for the distillation of bituminous It was not obvious that .such thin layers, in connection with a revolving ring plate furnace, could havea particularly advantageous action when employed for the distillation. Hitherto the distillation has almost universally beenfeffected in compactmasses, and the idea of-a very thin spreading of the material to be distilled is particularly fruitful in connection with a device by whichthis thin layer traverses a path of quite deli-- nite length in a quite definite time through a heating chamber, for it-is clear that the distillation in such a thin layer completel breaks with the. methods hitherto usual, an' that in consequence 'of the great output of the heating surface per unit of .time it must always be carried out continuously and with I clear that the suggestions (1) of emp'loying, for the distillation, in order to .produce half-coke and high grade tar oils, a revolving ring plate furnace, upon'the movable heat exchanging surfaces of which (2) the material is spread out in an extremely thin layer, presents technology with altogether vnew methods of low temperature coking,

" 'In the distillation of bituminous. sub stances it is of tremendous importance that the entire materialto be distilled should be' worked through quite uniformly, that is to temperature in allits parts. The inventors have ascertained that this uniform treatment is only possible in its entirety when layers of. material are employed which are very thin, that is to say, less than l'centimetre in thickness, as only then can it be guaranteed that the heating action is. the same upon all parts of the material. \Vith thicker layers the bottom layer of material undergoing distillation covering the heating surface of the furnace is unavoidably more strongly heated than the layer lying above it. Furthermore, the employment of such thin layers has also the further immense advantage that the escape of the gases from the mate rial undergoing distillation can take place immediately upon the attainmentof the corresponding degree of heat without any hindrance. By this means'the distillation process is very considerably shortened, that is to say, each square metre of heating surface will attain a very considerably greateroutput per unit of time.

This uniform treatment of the material undergoing distillation, is of such. great importance on account of the fact that only the uniformity of the temperature action upon all parts of the material makes it possible for thewhole of the final product obtained, that is to say, the whole of the coke or halfcoke accruing, to be of the same quality in all itsparts, that is'to say, for all its partsto contain the same proportion of gas.

. According to the treatment of these'parts,

besides the uniformity of the final product, that is, of the half-coke, the further result is obtained that the oils obtained by the distillation process from all parts of the material undergo'in distillation are of the same uality throug out, never varying during t e process.

It is also quite obvious that the knownprocess, according to which the oil-carrying vapours that become free in the various stages of the distilling process are'separately collected and separately worked up according to their percentage of valuable subtillation, a clean separation of these various grades of distillation gases obviously becomes-less possible, the thicker the layer is, for, as-stated, the thickness of the layer prevents a simultaneous and completely uniform treatment of the material. The porsay, that the material during the distillation process, should be exposed to the-same tions ,of the material adjacent to the heat exchangingsurface are treated more quickplate furnace,

layer, by

ly. Thus the gases of similar composition rise from the various superposed layers of material at differenttimes, distillation gases of different qualities mixing with one another, and the separate-collection is for the most part prevented or at least impaired.

The employment of a minimum thicknessof layer, in connection with a revolving ring erally a remarkably advantageous adjustabilityof the distilling and coking process.

The products to be obtained may be deter-- mined in advance asxregards theirk nd and quality, as soon as the ,two determining fac-j tors here are regulated, namely, (1)- -the desired maximum temperature at which distillation takes place, and the duration of the action of this maximum temperature upon the material undergoing distillation. By'the spreading of a more or less thin regulating the speed of the work ing plate of the revolving furnace, and also by regulating the heating "of this rotating working plate, tlie-possibil-ityis provided in practice of determining at will the quality' of the halfscoke accruing'and also the quality of the oils accruing.

In the accompanying structional example is illustratedof a furnace inqwhich thenew process can be carried out. In jthese'drawings I Fig; lshows in sectional elevation through the centre such a furnace with an annular below by the lateral heating flues c is renrevolving hearth,

Fig. 2 shows on a larger scale part of the working, plate of the hearth with the layer resting thereon.

- In the constructional exampleill-ustrated,

a is, an annular furnace crown, thefurnace'.

chamber of which is open at the bottom and is closed by the annular hearth b. i

In the constructional example shown,

there are arranged in the crown of the furnace annular heating flues 0, which serve to heat the hearth plate'from below. Further heating flues (Z may also be employed for heating the hearth plate from above.

The revolving hearth consists of two superposed hearth plates 0 and f rigidly connected with-one another. The lower plate 6 serves to close the furnace from the exterior and the upper plate 7 is the actual working hearth and serves for-the receptioif'of the material undergoing treatment. The interval of space between the plates '6 and f is made so great that radiant heating from dered. possible. and rest y means of a carrying ring 9 upon a Thes-two hearth plates 6 carriage h, which runs upon a railway '2.

The carriage '70 carries a ringof teeth is,

'which can be rotated by means of any convenient driving device Z. For the spreading .of the fine-grained or pulverulent material ,justably secured to the fillin renders possible quite gen-a u'ay'as drawings one con- 1 rigidly connected with one another millimetres. By this means the thickness of the layer spread is determined. The gases and vapours rising from the material may be drawn olf from the furnace through suction tubes q. distillation of bituminousTsubstancrs, a plurality of suction=ti1bes 9 may be arranged at such. positions that the various fractions of the oilsobtained are collected separately.

The heating fiues'c and 01 may be heated by any; convenient heating gases.

lVhen usin tion of a habokefor example from peat, li'gnite, or any other bituminous substance,

.the fine-grained pulverulent or similar mate rial. is shot in through the tube 0 and falls .out of the filling box n on to the hearth The health 7, moving forward underneath the filling box a, takes with it a layer of material a' few millimetres th'iek,-the excess being scraped off by the ledge-p. During its passage through thefurnace the material is distilled, the heating action being effected with extreme quickness 'inconsequence of the exceptionalthinness of the layer. Be-

When'it is a question .of the the furnace for the produc-- A knife-like ledge 12 is adthe hearth there remains a gap of a few fore the material travelling through the-- furnace chamber returns to the spreading point the coking is finished to thedesired extent. The material: may therefore be discharged byany suitable means "shortly before it reaches the filling point m again.

1. In the process'of distilling and coking solid carbonaceousmaterial on annular revolving hearths, the steps" which comprise maintainingfa layer of such. m aterial on the hearth in a thickness lessthan one centimeter and subjecting the material to a coking heat until coked.

2'. Inthe process of distilling and coking solid carbonaceous material on annular revolving hearths, the steps which comprise v maintaining a layer of such material on the hearth in'. a thickness less than one centimeter and subjecting the material to a coking heat until coked, said heat being suflicient to complete the-coking in one revolution of the hearth.

an the process of distilling and coking solid carbonaceous material on annular revolving hearths, the steps which comprise maintaining a layer of such material on the hearth in a thickness of about one to three millimeters and subjectingthe material to a coking heat until coked, said heat'being a coking heat until coked. sufiicient to complete the coking in one 0 v 4. In the process of distilling and coking revolution of the hearth. solid carbonaceous material on annular re- In'testimony whereof we. have signed our 5 volving hearths, thesteps which comprise names to this specification.

maintaining a layer of such material on the hearth in a thickness of about one to three LUDWIG HONIGMANN. millimeters and subjecting the material to w FRIEDRICH BARTLING. 

